Bald over by Aguilera's hair

In her pursuit of pop superstardom, she has experimented with a vast array of hair colours and styles.

There have been jet-black or blonde curly locks, dreadlocks, extensions and a mixture of all four.

But it appears that this addiction to hairdressing has taken its toll on Christina Aguilera's crowning glory - she seems to have developed bald patches.

The first sign that Miss Aguilera, 22, was losing her hair came last month.

While dining with friends at The Ivy in Los Angeles, her messy, jet-black hairstyle failed to cover a patch of scalp on the right side of her head.

At the Q Awards earlier this month, she was seen fiddling with her hair in a vain attempt to distribute it more evenly about her head.

A guest at the ceremony in Park Lane Hotel said: 'I was sitting behind Christina and she wouldn't leave her hair alone. On the front, righthand side of her head there was a patch of scalp visible.'

Trichologist Philip Kingsley, author of The Hair Bible, said: 'Hair extensions often cause bald patches where they have gripped the scalp. It doesn't matter how they are applied, when the extensions are removed they can pull out a lot of hair.

'Having tight plaits - or dreadlocks - also causes problems, often leading to bald patches called traction alopecia.

'This means the hair has been pulled so hard to form the plaits that it falls out when they are taken out - although it does usually grow back.'